Lithium-ion batteries have become increasingly popular in recent years as secondary or rechargeable batteries, because of their relatively high energy density and specific power, and their ability to hold a charge over time, compared to traditional batteries, such as lead-acid, nickel cadmium, nickel metal hydride batteries and the like. A typical lithium-ion battery includes one or more electrochemical cells, wherein each cell includes an anode (e.g., an intercalated lithium compound), a cathode (e.g., including a metal oxide) and a liquid electrolyte (e.g., a lithium salt in an organic solvent). Although such cells may work for some applications, the liquid electrolytes employed in such cells may leak from the cells and are often flammable; therefore use of such batteries can pose safety hazards.
To address the safety concerns regarding lithium-ion batteries, solid-state lithium ion cells have been developed. Unfortunately, however, solid-state cells generally have relatively low ionic conductivity through the solid electrolyte, poor rate capability, and insufficient loading of active material, compared to traditional lithium-ion cells, having a liquid electrolyte. In addition, solid-state cells often exhibit interfacial instability.
Lithium metal (e.g., lithium foil) is often avoided as anode material for solid state batteries because of the interfacial instability of lithium with the solid electrolyte material. The lithium metal tends to react with and degrade or break down the electrolyte, which causes irreversible cycling of and therefore shortened cycle life of the solid-state cells. Accordingly, improved solid-state electrochemical cells suitable for use as secondary batteries, batteries including the cells, and methods of forming the cells and batteries are desired.